Does psychiatric comorbidity increase the length of stay in general hospitals?

Several studies reported that in non-psychiatric hospital departments mentally ill patients have a longer length of hospital stay than mentally well. But their methods are often limited because other predictors of length of stay were excluded from statistical analyses. Using the Clinical Interview Schedule, research psychiatrists interviewed 993 patients of medical, surgical, gynecological, and rehabilitation departments in Austria. Using several multiple regression analyses, the influence of psychiatric comorbidity and other variables on length of stay was analyzed. 32.2% of all patients suffered from psychiatric morbidity. Of all psychiatric cases, 6.2% received more than one psychiatric diagnosis. Presence of psychiatric disorders, age, a diagnosis of neoplasms, number of all somatic diagnoses, and the number of previous non-psychiatric hospital admissions predicted length of stay. Patients with dementia, with substance abuse disorders, and with alcohol- and drug-related psychiatric disorders showed a significantly increased length of stay, while other psychiatric diagnoses did not differ from the mentally well. Even after controlling for confounding variables, dementia and substance related diagnoses increase the length of hospital stay. It is important to investigate interventions for early recognition and treatment of these disorders.